Toshiba ER6VCT PLC Replacement Battery 3.6V 2700mAh

Toshiba ER6VCT / LS14500-PR — 3.6V Li-SOCl2 Replacement Battery

This is a 3.6V Li-SOCl2 cell rated at 2700mAh (9.72Wh), built to the AA-size form factor at 51.00 × 16.30 × 14.60mm. It fits Toshiba ER6VCT and LS14500-PR PLC backup battery slots. The cell maintains SRAM program memory and real-time clock data during main power loss in industrial control environments.

• ER6VCT and LS14500-PR compatibility: Both part numbers share the same AA-sized Li-SOCl2 cell footprint, 3.6V nominal voltage rail, and passive current draw profile. The PLC's memory backup circuit draws microamp-level standby current — Li-SOCl2 chemistry handles that load without the voltage sag that Li-ion or NiMH cells would introduce at those current levels.
• Bench tested on actual hardware: We measured open-circuit voltage on arrival, confirmed passive discharge behaviour across the cell's internal bobbin construction, and verified the cell holds above 3.5V under the microamp draw typical of PLC SRAM retention circuits.
• Hot-swap procedure for this PLC: Always replace this cell with the controller powered on and in RUN mode. Removing the battery while the PLC is powered off will clear SRAM contents. If that happens, reconnect your programming device and reload the program from backup before restarting the controller.

PLC losing program memory after battery swap

SRAM in most PLCs using this cell has no capacitor-backed holdover — the battery is the only retention source. The instant the old cell is removed with the controller off, SRAM loses power and the program is gone. The fix is straightforward: power the PLC on, confirm RUN mode, then swap the cell live. Most controllers in this class tolerate the brief voltage dip during the physical swap without faulting.

Battery alarm not clearing after a confirmed good installation

Replacing the cell does not automatically reset the battery fault flag in most PLCs that use ER6VCT-type cells. The alarm bit is latched in software and requires a manual reset through the programming terminal or HMI — the controller will not clear it on its own. Open your programming software, navigate to the fault or status register, and acknowledge or reset the battery alarm flag explicitly. On some controllers this also requires the new cell to read above 3.5V, so verify cell voltage at the terminals before clearing the flag.